This application generally relates to multichannel heat exchanger applications in heating, ventilation, and air-conditioning (HVAC) systems. The application relates more specifically to a refrigerant-storage refrigerant-storage vessel configuration for a multichannel heat exchanger coil of a condenser.
It should be noted that the present discussion makes use of the term “multichannel” tubes or “multichannel heat exchanger” to refer to arrangements in which heat transfer tubes include a plurality of flow paths between manifolds that distribute flow to and collect flow from the tubes. A number of other terms may be used in the art for similar arrangements. Such alternative terms might include “microchannel” (sometimes intended to imply having fluid passages on the order of a micrometer and less), and “microport”. Other terms sometimes used in the art include “parallel flow” and “brazed aluminum”. However, all such arrangements and structures are intended to be included within the scope of the term “multichannel”. In general, such “multichannel” tubes will include flow paths disposed along the width or in a plane of a generally flat, planar tube, although, again, the invention is not intended to be limited to any particular geometry unless otherwise specified in the appended claims.
In a typical multichannel heat exchanger or multichannel heat exchanger coil, a series of tube sections are physically and thermally connected by fins configured to permit airflow through the heat exchanger to transfer heat between the airflow and a circulating fluid such as water or refrigerant being circulated through the multichannel heat exchanger. The tube sections of the multichannel heat exchanger are oriented to extend either horizontally or vertically and each tube section has several tubes or channels that circulate the fluid. The outside of the tube section may be a continuous surface typically having an oval or generally rectangular shape.
Multichannel coils can offer significant cost and performance advantages compared to conventional round-tube condenser coils when used in an aircooled condenser. However, multichannel condenser coils have a much smaller internal volume than is available with conventional coils. ASHRAE 15-2004.9.11.4 states that “liquid receivers, if used, or parts of a system designed to receive the refrigerant charge during pump down shall have sufficient capacity to receive the pump down charge. The liquid shall not occupy more than 90% of the volume when the temperature of the refrigerant is 90° F. or 32° C.”. More particularly, the smaller internal volume in microchannel coils often requires a condenser that incorporate a refrigerant-storage refrigerant-storage vessel, which may be referred to as a receiver or a refrigerant-storage vessel, in order to hold the refrigerant change for pump down or servicing to meet this requirement. For examples of prior art related to receivers, see the ASHRAE Handbooks.
What is needed is a system and/or method that satisfies one or more of these needs or provides other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.